Treatment of copolymer olefins for oxonation



Nov. 10; 1953 Filed May 26, 1951 TQEA'rnJe vessel:

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ImTlAL Pom MEQ FEED C oLEFm5 AND cgLsFm DIMER9 TREATMENT OF COPOLYMER OLEFINS FOR OXONATION H 50 Acm RECYCLE' Cihar'Le s A. (f/chef).

CLifford w. muessig 15 63 OLEFIN5 I Acm I CHARGE. l

C OLEFIN Acw omens nEc cLE Ens/enters Patented Nov. 10, 1953 TREATMENT OF COPOLYMER OLEFINS FOR OXONATION- Charles A. Cohen, Roselle ark, and-curs rs ,WQ I Mllessig', Roselle, N. J., as'signorsto Standard v Oil Development Company, a corporation of Delaware Application May 26, 1951; seiialNacza sosf f 1 t This invention relates to a process for enriching an oxo reaction olefinic feedv with'certain types of branched olefin polymers, particularly under conditions that permit the olefinic hydrocarbons treatedand reacted to be readily recovered. v Complex mixtures containing mainly C7 to C12 olefin polymers with' various degrees of branchiness' are formed, by non-selective polymerization of 'propene-butene -feeds*contacted under pressures of 150 to about 1200p. sfii. g; pressure for to 200 seconds with phosphoric acid at 400 F.-5 00 This type of polymerization process has been {described in the art as the U. O.P. proce'ssr When the non-selective polymerization is operated to obtain maximum yields of C7 polymers by having up to 50% of normal buten and isobutene copolymerize with propene, a larger amount of the polymers formed have a structure less suitable for reacting with carbon monoxide and hydrogen in whatis known as the oxonation reaction. I I

It is an object of the present invention to provide an economically feasible method of treating branched polymershaving mainly? carbon atoms per molecule to concentrate those that are more satisfactorily oxonated and to separate the remainder of the polymers as useful hydrocarbons;

Although relatively. weak aqueous solutions of sulfuric acid havebeen known to have a hydrating effect on lower olel-l'ns and strong sulfuric acid solutions at more elevated temperatures have been known to have a polymerizing action on lower olefins, it appears that there has not been any knowledge hitherto about a selective polymerization effect of dilute aqueous sulfuric acid on mixtures of branched olefin polymers having at least? carbon atoms per molecule, especially the complex propene-butene copolymer mixtures.

The present invention is basedv on a discovery of the eifects of sulfuric acid controlled to have a strength in the range of 60 to 75 wt. per cent H2804 at temperatures ranging from 40 to about 100' F. on'short "contact with thefCl branched olefin polymermixtures. Using these conditions it was found that while a'portion of the polymers became transformed to higher molecular' weight polymers, substantially 'all the hydrocarbons separate as a hydrocarbon liquid phase from the ,moderately-low temperature aqueous acid solution. By vdecantingthe hydrocarbon liquid phase product,thenfractionally distilling therefrom C-z olefin polymers boiling ;in the range 'of 165 F. to 190 R, an olefin polymer iii product was collected for. a comparative ox onation reaction test Th oxonation test demonstrated thatthe thus treated- C7 polymers are substantially better adapted for oxonation leading to'g'ood yields of desired C alcohols that form;

certain improved ester plasticizers.

Thefdilute sulfuric acid treatment at moderately low temperatures was accordingly found to lend'its'elf to an eflective though simple, opera-- ticn which will be described with references to the diagrammatic flow plan in the'accompanying,

drawing, t

In the drawing, a continuous feed strealntof" mixed propene-butene copolymers is represented-a as being introduced byline l into a lower partpflj a treating vessel 2 to passcountercurrently; to a; stream of the dilute aqueous sulfuric acid introduced as a continuous stream'from line ,3 atan upper part of vessel '2. Any desired means for increasing mixing or intimately contacting the countercurrent streams may be used, in this connection. I t I The streamsof material/may be contacted for, a periodof 5 to 60 minutes in vessel {while have ing from to lo'volurnes of the dilute acid-per volume of hydrocarbon in thetreating zone of vessel}. a .7 A

The 'll'ydrocarbonfs'treamremaining as a separate liquid phase on reaching the top of the treat?- ing zone, abovethe inlet 3 6f 'theacid streamis withdrawnthrough line 4 to a fractional distillation zone'in tower 5. i

tom of the treatingzone in vessel2 is withdrawn by line 6 at a point below the 'inlet 1 of the hydrooarbon feed. This-withdrawn acid tends to contain only a small amount of the polymers and, can be directly returnedtothe treatingvessel 2' by line 1 for reuse,-because"on further contact with the upfiowing countercurrent hydrocarbons undergoing treatment, thesepolymers are washed out of the dilute acid. Thus, the'acid can be re-,

pea tedly used without undergoing change in strength and without requiring additional steps of recovering the acid.

The treating vessel 2 may be provided with ordinary means for maintaining controlled temperatures, but since the treatment is carried out suitably at average room or moderate temperatures of. about 40 F. to l no heat ngis necessary,}nor is refrigeration ordinarily required.

Since e tr a ment. r c ion l s selectivity when theacid strength approaches, 5; yol. .per 7 Qt l zfia fi is n eats i ast neths:a proache ing 50 vol. per cent H2804 the treatment reac-.-

The us d fdil'ute' sulfuric acid reaching meter-L tends to undergo reaction. The test results indi cate the critical requirements of the operation. 7

In the distillation column the hydrocarbons are heated to vaporize and distillfoil' C1 110cm olefin polymers, which are sums-ready more vols? tile than the higher molecular weight polymers formed in the treatment. The "distilled poly-1 mers can be withdrawn by overhead line 8. ordinary reboiling steam coil 9 in the bottom part of column 5 may supply the needed heat tor distillation oisteain 'may injected directly ai line m. -'r1ie syapr oduc cm po ers are Bottoms product by line it. y

' Kdditional treating v'essel 1 2715 connected into theoperation for tire; (:1 tom; polymers a second stage treatment; when they arepasse'd thereto-by line is; Here'againthejamd can be recycled byline]! a'sjin the first stage, and the treated polymzjs' are p sse -tr use to line t ii q qn rs nd xe a m of 9 o 5% strengthmay be added through line l8- to the c qleda n use. it l a a for 2 ear net b w n 70% flfiorstrength the acid treatment mdi fi"Qh ih ie mn ee mae str m 31 as ,d s d'vm i uifi ableio'i excitation. The remainder or tlfi y r e wbq yh c w re ha ed i h he P fi fi i j i w e d s l e lmd tj fi i d r sure nd new h na n i m i products boilingi'n the renew: or; to ca hydro- -crbons; The mat ai aia e an thwy emin fl' he seeds; an t 'hirdt a 'bor m e r ms iii ih -la 'im f rhas'e. l ss. a aeofies a e: the 'hydrocarbori mater-m was or the" separated 'acid" phase from; whicll it is removed upon recontact with fresh teed. mas instance was -any degradation of C 1 arenasto propylene memento chan cit'ed thaig the desired effective chang with acid from so 'at bei' ei eoqtthe -01 "lira- 4 remained nearly the same as the original reed. At above H2804, the treated 01 product recovered began to drop excessively in yield.

The C1 olefin polymers treated with approximately an equal volume 60 to 75% H2804 at 40-100? F. were analyzed for change in composition by infra-red absorption. The; thus-treated C1 olefin polymers were recovered 55 to by volume yield. Representative test results are given in the following tabulation:

The type of means is secor'aihgte the seam G a i alq s bsd WSchWfl; a Boar -jf 1. vo u e is Pa 7. 9.32 17. ifih mi ls- 43 w en? ir ieik fr qa e. Eff. repre en s I n alto/,1 esfiei i vt re y n 5 e v e' e s y m ,i i 'n ll de ine-l 1. a

. s. s ps il s ihifi reeves n 'ea re thatth'e: acid treatment could-increase favorably the qa q ii i ti nl t nei hr n hs ql n largely at the expense 01' type IIIbranched olefins.

.lltliq sh fi ej et, h one l b f e wer ne d drelafiie r l i ili a l a n na ve in th .ii t fia ationp s r Q alc h s. d r W iQE-PWWQW t r .p asi t t wa jt un tlithrl iin flbi h a ia s to? im lw h w amounts oi type present the oxonation yielded'a n alcohol p'roduct approximately asgood s t 2991 9? 9f ly efin enqevens ri thsrf q th ewes o 'tns i i e 31 3 9 iiaiiqn .inide wasp? .rin l...n est plasticized t t a t ss yi ihe; alc h "Ahrie f s ary of: evaluated es er pl asticizers is sites in the -f ollowing tabulation:

i izimi'mts from s eamer 'bzefln's' eeziz'aata zizastiaizers l outstanding impr vement obtained witlr lfliis 'i'n theoxa reee is inthe el'ong'a t'iorr steam riaih'e,k311isti'eizer. I 1 ei i i l 1. The; method "of treating traiicir dfoinn copolymers of propenes and butenes, said copolymers having at least 7 carbon atoms per molecule, which comprises contacting said copolymers with an aqueous solution of 60% to 70% H2804 at 50 to 100 F. to convert less than 50 volume per cent of the copolymers to higher polymers, separating the treated copolymers with said higher polymers from the aqueous acid solution, further treating the mixture of copolymers and higher polymers with an aqueous solution of 70% to 75% sulfuric acid to obtain further dimerization while still maintaining lessthan 50 volume per cent of the copolymers unreacted, and separating the treated copolymers with the dimerized copolymers from the aqueous acid solution.

2. In a process of preparing a feed for oxonation from C7 propene-butene copolymers, the improvement of treating said copolymers with an aqueous solution of 60% to 75% strength H2804 at 40 to 100 F. until between 15 and 50 volume per cent of said copolymers are dimerized, removing the dimerized copolymers with the remaining treated C1 copolymers from the aqueous solution, distilling the C7 copolymers thus treated from the dimerized copolymers to obtain a distillate having an increased content of C7 propenebutene co-polymers in which the double bond links together secondary carbon atoms.

3. The method of treating a mixture of branched heptenes which are co-polymers of propene and butenes including a substantial proportion of heptenes having the double bond between secondary carbon atoms and a substantial proportion of heptenes having a double bond between a tertiary carbon and a primary carbon,

which comprises treating said mixture of copolymers by contact with 60-75% strength sulfuric acid in aqueous solution at to 100 F. until 15 to volume per cent of said co-polymers are dimerized to leave the remaining co-polymers unchanged in molecular weight with an increased concentration of heptenes in which the double bond is between secondary carbon atoms and a decreased concentration of heptenes having a double bond between a tertiary carbon and a primary carbon, and removing the dimerized co-polymers with the unchanged co-polymers as they are separated from the aqueous solution of the acid.

4. The method of claim 3, in which a small amount of the dimerized co-polymers remain in the aqueous acid solution from which the treated co-polymers are removed and said aqueous acid solution containing the small amount of co-polymers is contacted with countercurrent stream of the co-polymers being freshly treated.

CHARLES A. COHEN. CLIFFORD W. MUESSIG.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,007,160 Engs et al. July 9, 1935 2,128,971 Snow Sept. 6, 1938 2,320,256 Bailey May 25, 1943 2,504,682 Harlan, Jr. Apr. 18, 1950 2,530,989 Parker Nov. 21, 1950 2,552,508 Peters May 15, 1951 2,557,701 Smith June 19, 1951 2,564,914 Murray Aug. 21, 1951 

1. THE METHOD OF TREATING BRANCHED OLEFIN COPOLYMERS OF PROPENES AND BUTENES, SAID COPOLYMERS HAVING AT LEAST 7 CARBON ATOMS PER MOLECULE, WHICH COMPRISES CONTACTING SAID COPOLYMERS WITH AN AQUEOUS SOLUTION OF 60% TO 70% H2SO4 AT 50* TO 100* F. TO CONVERT LESS THAN 50 VOLUME PER CENT OF THE COPOLYMERS TO HIGHER POLYMERS, SEPARATING THE TREATED COPOLYMERS WITH SAID HIGHER POLYMERS FROM THE AQUEOUS ACID SOLUTION, FURTHER TREATING THE MIXTURE OF COPOLYMERS AND HIGHER POLYMERS WITH AN AQUEOUS SOLUTION OF 70% TO 75% SULFURIC ACID TO OBTAIN FURTHER DIMERIZATION WHILE STILL MAINTAINING LESS THAN 50 VOLUME PER CENT OF THE COPOLYMERS UNREACTED, AND SEPARATING THE TREATED COPOLYMERS WITH THE DIMERIZED COPOLYMERS FROM THE AQUEOUS ACID SOLUTION. 